The former Superbowl MVP announced his retirement from pro football Friday afternoon, according to the Associated Press.

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"It's been 12 unbelievable years, some of the best years of my life," Warner said. "But I want everybody to know that I'm just as excited about the next 12, that I'm excited about what lies in front of me. I'm excited about spending more time with my family, and seeing what God's going to do next."

After a rough start in a league that initially turned him away, the 38-year-old Iowa native has become one of the most respected players in professional football. His roller coaster career through the NFL has taken him to three Super Bowls and earned him two NFL MVP awards.

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Cardinals coach Ken Whisenhunt said Warner was "at the top" of players he has coached. "He’s one of the best quarterbacks in this league,” he said, “and I think it’s well noted that he’s one of the best people I’ve been around.”

But Warner has seen his share of disappointment as well. He famously stocked shelves at a grocery store in Cedar Falls for $5.50 an hour after being passed over by the Green Bay Packers training camp after college. The four time Pro Bowler was finally picked up by the St. Louis Rams in 1998, who then unceremoniously shipped him off to Europe to play for the Amsterdam Admirals.

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After a series of injuries to first string QB's, Warner was tapped as starting quarterback for the Rams in 1999 and silenced his doubters by putting together one of the top seasons by a quarterback in NFL history, and ended up toppling the Tennessee Titans in Super Bowl XXXIV. After a successful run with St. Louis, Warner was picked up by the New York Giants, who also gave him the shaft when they promoted Eli Manning to starting quarterback after nine games.

Warner finished out his career in Arizona, where he was again passed over for unproven draft pick Matt Leinart. After injuries and a disappointing season from Leinart, Warner was took the helm again in 2008 and led the Cardinals to another Super Bowl appearance the next year.

"He has had a dominant career. He’s a good person...it's a good thing," said Cardinal's defensive tackle Darnell Docket of Warner's retirement. "If you're going to go out, go out on top."

Warner's career statistics will surely keep in the running for Hall of Fame consideration -- even though he started his first game at 28. In a comparison with the 14 quarterbacks to make the Hall of Fame in the last 25 years, Warner has a better career completion percentage, yards per pass attempt and yards per game. Only Dan Marino had more career 300-yard passing games.

Off the field, Warner is known for his charitable work, including his First Things First Foundation, which helps out children's hospitals, people with developmental disabilities and single parents. He's also known for his religious devotion and controversially starred in a commercial opposing a bill supporting embryonic stem cell research that aired during the 2006 World Series.

Cardinals general manager Rod Graves said Warner's exit is emotional "because I realize once again how extraordinary he was.”

“I’ve only had the privilege of being around one other person that I can say was close to him and that was Walter Payton,” Graves said. “I think when you have an extraordinary player and one who is just as extraordinary off the field, then you realize you were in the presence of someone special.”

Warner's departure puts pressure on Heisman trophy winner Leinart, who again takes the reigns as the Cardinal's starting QB.